The Doppler ultrasound image shows an elevated peak systolic velocity (PSV) of 637 cm/s, an elevated end-diastolic velocity (EDV) of 312 cm/s, and a low resistive index (RI) of 0.51 at the arterial anastomosis of a renal transplant. These findings are characteristic of significant renal artery stenosis (RAS) at the transplant vascular anastomosis.

Key sonographic features of renal artery stenosis:

Peak systolic velocity (PSV) > 250–300 cm/s at the stenotic segment (this case: 637 cm/s)

Post-stenotic turbulence with spectral broadening

Low resistive index (RI < 0.56 suggests downstream vasodilation)

Elevated acceleration time (AT > 0.07 sec), and reduced acceleration slope

Aliasing on color Doppler due to high velocity

In this image, the marked increase in velocity with spectral aliasing and low RI is diagnostic of transplant renal artery stenosis — the most common vascular complication post-transplant, typically occurring at the site of surgical anastomosis.

Differentiation from other options:

A. Iliac arteritis: A rare condition, not typically presenting with these Doppler changes.

C. Renal vein thrombosis: Would show reversed or absent diastolic flow, not elevated systolic velocities.

D. Arteriovenous malformation (AVM): Produces a high-velocity, low-resistance waveform but is associated with color bruit, aliasing, and pulsatile venous waveforms — not evident here.

Urinomas are collections of urine in the retroperitoneum that result from trauma, surgery, or obstruction causing urine leakage. Trauma is a frequent cause of urinoma formation due to disruption of the urinary tract.

According to Rumack’s Diagnostic Ultrasound:

“Urinomas may develop as a complication of trauma, surgery, or obstructive uropathy with urinary extravasation into the retroperitoneum.”

The ultrasound image demonstrates diffuse increased echogenicity of the liver parenchyma with posterior beam attenuation (acoustic shadowing), findings that are consistent with hepatic steatosis (fatty liver disease). The liver appears brighter than normal, and the vascular markings, particularly of the portal veins, are obscured due to the increased parenchymal echogenicity.

Hepatic steatosis refers to the abnormal accumulation of fat within hepatocytes and is commonly associated with obesity, diabetes, alcohol use, and metabolic syndrome.

Classic sonographic features of hepatic steatosis include:

Diffuse hyperechogenicity (“bright liver”)

Poor visualization of intrahepatic vessels and diaphragm

Posterior acoustic attenuation

Increased hepatic echogenicity relative to the renal cortex

Differentiation from other options:

A. Acute hepatitis: Usually presents with normal or slightly decreased echogenicity, "starry sky" appearance due to prominent portal triads and periportal edema.

C. Medullary sponge kidney: A renal condition with echogenic medullary pyramids, not hepatic.

D. Acute medical renal disease: Affects the kidneys, often with bilateral renal enlargement and increased cortical echogenicity—again not related to liver imaging.

The ultrasound image demonstrates a well-defined, ovoid, hypoechoic to isoechoic mass within the subcutaneous tissue of the abdominal wall. The lesion appears compressible and shows linear striations parallel to the skin surface — a classic appearance of a lipoma.

Lipomas are the most common benign soft tissue tumors and frequently arise in the subcutaneous tissue. They are composed of mature adipose tissue and are typically asymptomatic unless large or compressing adjacent structures.

Sonographic features of a lipoma:

Isoechoic to mildly hyperechoic or hypoechoic relative to subcutaneous fat

Oval or elliptical in shape with well-defined margins

Internal linear striations or “feathered” echotexture

Compressible and non-vascular on Doppler imaging

Located in subcutaneous fat plane parallel to the skin surface

Differentiation from other options:

B. Fibroma: Typically appears as a homogeneous, hypoechoic mass but is far less common in the abdominal wall.

C. Desmoid: Appears as an ill-defined or infiltrative mass within deeper soft tissues; more heterogeneous and may distort surrounding tissue planes.

D. Metastasis: Often more irregular, heterogeneous, and may show increased vascularity or invasion into adjacent structures.

The left lobe of the thyroid is located anterolateral to the esophagus. On transverse ultrasound imaging, the esophagus can often be seen posterior to the left thyroid lobe as a circular structure with echogenic mucosa and hypoechoic muscular layer. The longus colli muscle lies posterior to the thyroid. The thyroid is anterior to the trachea but this refers more to the isthmus or midline portion.

According to Rumack’s Diagnostic Ultrasound:

“The esophagus is seen as a target-shaped structure posterior to the left thyroid lobe; thus, the thyroid lobe is anterolateral to the esophagus.”

The tunica albuginea is a dense fibrous capsule surrounding the testis. Discontinuity of the tunica albuginea on ultrasound is diagnostic of testicular rupture — a urologic emergency that requires immediate surgical repair to preserve testicular function and viability. Early surgical intervention within 72 hours has a high success rate for testicular salvage (up to 90%).

Intratesticular hematoma (A) may be managed conservatively if the tunica albuginea is intact.

Heterogeneity of the parenchyma (C) indicates injury but not necessarily rupture.

Increased vascularity (D) may be seen with inflammation or reperfusion but does not mandate surgery unless rupture is present.

Reference Extracts:

Dogra VS, Bhatt S. "Acute painful scrotum: ultrasound evaluation." Radiologic Clinics of North America. 2004; 42(2):349-363.

Middleton WD, Kurtz AB, Hertzberg BS. Ultrasound: The Requisites. 3rd ed. Elsevier, 2015.

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The ultrasound image shows a classic “target sign” or “donut sign,” characterized by concentric rings of alternating echogenicity. This sonographic finding is pathognomonic for intussusception, particularly when seen in the transverse plane.

Intussusception occurs when a segment of bowel telescopes into an adjacent segment, typically in children aged 6 months to 3 years. It commonly presents with intermittent abdominal pain, vomiting, and sometimes “red currant jelly” stools.

Key ultrasound features of intussusception:

Target sign in transverse view (concentric rings of bowel layers)

Pseudokidney or sandwich sign in longitudinal view

May show intraluminal mesenteric fat or vessels dragged in with the intussusceptum

Comparison of answer choices:

A. Bowel obstruction may show dilated loops of bowel with air-fluid levels and to-and-fro peristalsis but lacks the concentric ring sign.

B. Diverticulitis typically shows bowel wall thickening and pericolic fat stranding; not the concentric target appearance.

C. Appendicitis may appear as a blind-ending tubular structure ( > 6 mm), not with concentric ring pattern.

D. Intussusception — Correct. The image demonstrates the classic target sign seen with this condition.

The clinical presentation—tender, swollen breast with erythema and fever—in a lactating female strongly suggests acute mastitis. The sonographic findings support this diagnosis. In the image, the breast parenchyma shows diffuse, hypoechoic, and heterogeneous echotexture with increased vascularity, which is consistent with inflammatory changes typical of mastitis.

Mastitis is a common complication during lactation, particularly in the first few weeks postpartum. It results from milk stasis and subsequent bacterial infection, commonly due to Staphylococcus aureus. Ultrasound features of mastitis include:

Ill-defined, hypoechoic, edematous areas in the breast parenchyma

Increased Doppler flow due to hyperemia

Skin thickening

Ductal dilatation may also be present

If left untreated, mastitis may progress to abscess formation, which would appear as a localized, complex fluid collection with peripheral hyperemia and internal debris. However, the image does not show a well-formed fluid collection consistent with abscess.

Option B (Ductal carcinoma): Inappropriate here due to the acute clinical scenario and patient age. Ductal carcinoma typically presents as a hypoechoic mass with irregular margins and posterior shadowing, not diffuse edema or inflammatory changes.

Option D (Galactocele): This benign milk-filled retention cyst typically appears anechoic or with fluid–fluid levels but lacks signs of inflammation and systemic symptoms such as fever.

Option A (Abscess): This could be a differential, but abscesses usually present with a well-defined anechoic or complex mass. The absence of a discrete collection and the diffuse appearance makes mastitis more likely.

Branchial cleft cysts are congenital epithelial cysts that typically occur laterally in the neck, often anterior to the sternocleidomastoid muscle, and lateral to the thyroid gland. The second branchial cleft cyst is the most common type and is found in the lateral neck region.

Medial (B) would be more consistent with thyroglossal duct cysts.

Anterior (C) or posterior (D) do not specifically describe branchial cyst location relative to the thyroid.

Reference Extracts:

Som PM, Curtin HD. Head and Neck Imaging. 5th ed. Elsevier, 2011.

Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th ed. Elsevier, 2017.

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